<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    <style>
        .setColor {
            color: red;
        }

        .setFontSize {
            font-size: 38px;
        }

        .setBorder {
            border: 1px solid springgreen;
        }
    </style>
</head>

<body>
    <div id="app">
        <div :class="[index1, index2, index3]">欢迎来到蜗牛学苑！</div>
    </div>
    <script>
        let vm = new Vue({
            el: "#app",
            //data指的是model
            data() {
                return {
                    index1: 'setColor',
                    index2: 'setFontSize',
                    index3: 'setBorder',
                }
            }
        });
    </script>
</body>

</html>